Metallic filling for cold accumulators



June 9, 1931. M. FRANKL 1,808,921

METALLIC FILLING FOR GQLD ACCUMULATORS med July 21, 192s AAAAAAAAA dPatented June 9, 1931 UNITED STATES PATENT OFFICEv MATHIAS FRNKL, 0FAUGSBURG, GERMANY, ASSIGNOR TO PHILIP? AUGUST WEYD- MANN, 0F VIENNA,AUSTRIA- METALLIC FILLING FOR COLD ACUMULATORS l S U E D Application ledJuly 21, 1928, Serial No. 294,356, and in Germany August 1, 1927.

The object of the present invention is to provide a cold accumulatorsuitable for use in the process described in patent application, SerialNumber. 81723, process for separation'- otgas-mixtures, especially ofair, in which the exchange of cold is effected by means of regeneratorsarranged for reversed operation. The cold accumulator used in. thisAprocess consists of a cylindrical or square shell 'of sheet"`inetalthrough whlch the air or other gaseous mixture flows in axial directionbetween a number of strips of sheetmetal disposed inside the shell at adistance of from 0,5 to 2,5 mm. apart from one another, whereby anexchange of cold or heat is effected. As the specific heat of iron atvery low temperatures is considerably less than at atmospherictemperature and also the volume of gas decreases with sinkingtemperature, while the specific heat of gas remains fairly even, a formof filling for the cold accumulator had to be devised which takes thesefacts into account. Inside the cold accumulatore `the temperaturedecreases from top to bottom, also the volume of gas and the specificheat of the iron filling of the accumulator. This latter at minus A190"C. amounts only to 0,036 as compared to 0,11 at plus C., that is twothirds less. vThe volume of gas decreases at about the same rate. Thefilling must, therefore, be so constituted that its mass toward thebottom or cold zone of the accumulator is greater .than at the top orwarmer zone and, therefore, the total fiow area for the gas diminishestoward the colder end.

In the accompanying drawings, which shows a preferred embodiment ot theapparatus according to the invention.

Fig. 1 is a front view of the cdld accumulator with parts of the shellremoved to show the filling strips of sheet metal;

Fig. 2 is a transverse section of the shell, the left side of the gurerepresenting a section along a line A-B of Fig. l, the iight sideasection along a line O-D of Fig. 3 is a side view of two sheet metalstrips one behind the other, the'one in front being drawn in full lines,the rear one in dotted lines;

Fig. 4 is a top view of the same;

Fig. 5 is a side view of the same; the left side of the figurerepresenting the front strips, the righthand side of the figure thestrip lying behind, part of the front strip having been removed;

Fig. 6 shows the filling in course of manufacture.

According to the invention the strips of sheet metal are disposed insidethe shell at distances apart which decrease by steps from top to bottomof the shell7 as may be seen from Figs. 1 and 2, resultino` in smallerspaces in the lower parts and orming narrower channels or passagesappropriate to the diminishingair volume at falling temperature. Theshell a is shown cut open in three places to expose to View the stripsof sheet metal constituting the filling. In cylindrical shells thestrips are disposed in spirals forming disks of from 500 to 1500 mm.diameter, as shown in Figs. 2 and 6; in square shells the st-rips areput in singly, in which case they must be shaped in such a way, thatintervening spaces of the desired dimensions result.

To attain thel highest possible effect the strips of sheet metal shouldbe corrugated and so arranged that a brisk whirling of the air flowingthrough the channels formed by them is brought about. The strips maytouch one another only in points, in no case along a line or plane,because the gas cannot reach laces where the strips touch, so thatportions of the cold-exchanging surface are thereby renderedineffective.

With a view to minimize losses from this' cause the strips are providedwith corrugations running aslant towards the edges of the strips; byarranging the corrugations -of neighboring strips to slant in oppositesense, the strips will touch only at the corrugations which is thedesired way, i. e. there will be point contact only. The crossing of thecorrugations also causes lively whirls in the gas current, thusconsiderably increasing the cold-exchanging effect.

Fig. l shows the shell cutopen in three places to expose. the filling toview; on the left-hand side the front strip is seen, while at the rightis shown the strip which lies behind. The corrugations of the upperstrips and o are higher than those of the middle strips cl and e and otthe lowest f and g, as seen in Figs. 1 and 2.

Fig. 2 shows the filling of a cylindrical cold accumulator in transversesection.. In this spirally wound filling two strips with corrugationsslanting in opposite sense are always wound simultaneously, thus forminga double-wormedspiral with corrugations lying crossways. This is seenvery plainly in Fig. 6 which shows the spiral winding in course ofmanufacture, that is in the unfinished state. The strips d and a arepreliminarily drawn through pairs of furrowed rollers h and t, and k andl, to corrugate them. The strips are laid next to one another and thenspirally wound around the axle m of the cold accumulatorl a,

The accumulator described above is of particular advantage in theregenerative refrigeration of gases for the purpose either of separatingthe componentsv of a mixture of gases, or of removing the moisture orcarbon dioxide therefrom. In such case, at least two cold aceumulatorsof the type shown in Fig.` l must be present. At the beginning of theprocess employing the above-described accumulator, the metallic stripscomprising the filling or packing of the accumulator are cooled by meansof a refrigerating machine to the temperature at which the Vparticulargi s mixture being treated, for example, air, is to be separated intoits components, or at which water vapor or carbon dioxide willprecipitate from air or an'y other gas. The air or other gas is thenintroduced at the top of the first accumulator, which at this stage ofthe process acts as a cold exchanger, and which gives up its cold tosuch air and cools the same to the desired temperature. After that theair is separated into its components, or water vapor or carbon dioxideis precipitated in a suitable apparatus, after which in this mannertransferred to the packing of the second accumulator. The components orgases escaping from the second accumulator are almost as warm as the gasintroduced into the first accumulator.

After about five minutes, the flow of gas is reversed, and the gas to betreated is fed first through the second accumulator and passed outthrough the first accumulator, so that it is cooled in the second andgives up its cold to the first accumulator. After about five minutes theoperation is again reversed and the gas to be treated is againintroduced into the first accumulator. The accumulator described abovethus operates alternately as cold accumulator and cold exchanger in aregenerative retrigerating system, and is to be distinguished from theknown forms of tubular cold exchangers which operate continuously.

I claim:

1. `A cold accumulator comprising a shell, the inside space of suchshell being divided into a number of zones, strips of sheet metaldisposed in each ot said zones and adapted to be chilled by a stream ofcold gas passing through the accumulator and to cool av subsequentstream of warmer gas. said strips disposed in such a way that from zoneto zone the extent of their surface. and the mass ot metal toward thecolder end become greater, while the total How area of the gas channelsbecomes smaller.

2. A cold accumulator comprising a shell, an axle in said shell, theinside space of said shell being divided into a number of zones, diskscomposed ot two parallel strips of sheet metal'adapted to be chilled bva stream of cold gas passing through the accumulator and to cool asubsequent stream of warmer gas, said strips being wound spirally aroundthe axle of the. shell in each of said Zones. and being provided withcorrugations aslant to the direction of the gas current, thecorrugations of each pair of said strips lying erossways.

3. A cold accumulator comprising a cvlindrieal shell, an axle in saidshell, the inside space oii said shell being divided into a number ofzones lving below one another` disks composed of two parallel .strips ofsheet metal adapted to be chilled b v a. stream of cold gas passingthrough the. accumulator and to cool a subsequent stream of warmer gas,said strips heilig wound spirally around the axle of the shell in eachot said zones, and provided with corrugations aslant to the direction ofthe gas current, the corrugations of each pair of said to a secondaccumulator from the bottom to the top thereof. This second accumulatornow operates to store in its packing the cold of the dischargingcomponents or gas; in effect, the cold of the first accumulator is 4. Acold accumulator comprising a shell. an axle in said shell. the inside.space ot said shell being dividedinto a number of zones, two parallelstrips of sheet metal adapted to be chilled by a stream of cold gaspasssignature.

MATHIAS FRANKL.

